1. Field of the Invention
The present invention pertains to a method and to a device for filling a plurality of containers in cycles, especially for use in the packaging of pharmaceutical products.
2. Description of the Related Art
These types of devices have been used for many years, and in the pharmaceutical industry they serve, for example, to fill bottles or tins with tablets. In the standard case, a conveyor belt or screw conveyor, moving in cycles, is used, which carries the containers to be filled to stationary filling stations and takes them away again. Examples of these types of filling devices are known from EP 1 035 023 A1 and WO 2006/016268 A1.
So that the highest possible throughput can be achieved during production and so that there is no need to interrupt the continuous transport of the containers before and after they have been filled as described above, the containers to be filled can be transferred to an intermediate storage unit, which operates in cycles and thus makes it possible for the filling operation to take place in stationary filling stations.
A device in which the products being supplied continuously on a one-by-one basis are collected and stored and can be taken from it again in groups in a cycled manner is known from DE 37 24 839 C2. This known device comprises an endless conveyor chain traveling around two rotatably supported deflecting pulleys mounted a fixed distance apart, the chain being provided with compartment-forming drivers to accept and to transport the products being supplied one-by-one. It also comprises a slide, on which the two deflecting pulleys are mounted.
With the help of the device known from DE 37 24 839 C2, it is possible for example, to fill an entire group of supplied bottles with tablets simultaneously at the stationary filling stations. For this purpose, the bottles conveyed one-by-one by a conveyor belt are transferred to the endless conveyor chain. The group of bottles which has been moved up to the stationary filling stations is held in the filling position for the duration of the filling operation by a translational movement of the slide in the direction opposite that of the endless conveyor chain, and after the bottles have been filled, the slide is moved by the same distance as that which it traveled during the filling operation in order to carry away the group of bottles now filled with tablets and to bring the next group of bottles to be filled into the filling position.
The disadvantage of this is that the group of bottles already filled with tablets undergoes considerable acceleration as a result of the rapid translational movements of the slide and of the endless conveyor chain, which are both moving in the same direction and the speeds of which are therefore additive. As a result, it is possible for centrifugal force to cause individual tablets to fall out of the filled but as yet unsealed bottles. There is thus the risk that the number of tablets which should be present according to the production quality standard is no longer the same as the number of tablets actually present. The quality characteristics defined for the filling process therefore cannot be maintained.